US3832891A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ocular tension measurement
Assignee: STUCKEY INVESTMENTS Pty Ltd
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Filing: 1972-12-29
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Granted: 1974-09-03
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Expires: 1992-12-29
Abstract
Abstract An applanation tonometer which utilizes the principle of total internal reflection to permit use thereof by an optholmologist. The tonometer comprises a member of pre-determined weight which is adapted for longitudinal sliding movement in and from a support and for resting upon the cornea of a patient. The end of the member which is rested upon the patient''s cornea is formed from a material which has a refractive index approximately equal to that of tear film fluid whereby an area applanated by the member may be viewed at an angle incident to the plane of applanation.
Inventors
- 👤 G Stuckey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:15
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/16
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
186 words
An applanation tonometer, comprising, in combination: a. an elongate member of predetermined weight adapted for longitudinal sliding movement within and from one end of a sliding support therefor; b. at least one end portion of said elongate member being solid and formed from a transparent material having a refractive index approximately equal to that of tear film fluid; c. said end portion of said elongate member including a planar wall observation surface which is disposed substantially parallel to the longitudinal axis of said elongate member; d. a terminal end surface of said one end portion of said elongate member being marked to define an area of predetermined width; e. said terminal end surface being adapted for resting upon the cornea of the subject''s eye; and f. the area of contact between said terminal end surface of said elongate member and said eye being visible when viewed through said observation surface and at an angle which is obliquely incident to said area of contact by virtue of said end portion of said elongate member having a refractive index approximately equal to that of said tear film fluid.
Claim 2
Dependent Claim
186 words
An applanation tonometer, comprising, in combination: a. an elongate member of predetermined weight adapted for longitudinal sliding movement within and from one end of a sliding support therefor; b. at least one end portion of said elongate member being solid and formed from a transparent material having a refractive index approximately equal to that of tear film fluid; c. said end portion of said elongate member including a planar wall observation surface which is disposed substantially parallel to the longitudinal axis of said elongate member; d. a terminal end surface of said one end portion of said elongate member being marked to define an area of predetermined width; e. said terminal end surface being adapted for resting upon the cornea of the subject''s eye; and f. the area of contact between said terminal end surface of said elongate member and said eye being visible when viewed through said observation surface and at an angle which is obliquely incident to said area of contact by virtue of said end portion of said elongate member having a refractive index approximately equal to that of said tear film fluid.
Claim 3
Dependent Claim
53 words
An applanation tonometer according to claim 1, wherein: a. said end portion of said elongate member is generally cylindrical in form, except for a planar circumferential wall portion; and b. a stem portion projects axially outwardly from said elongate member in a direction opposite to that of said terminal end of said member.
Claim 4
Dependent Claim
32 words
An applanation tonometer according to claim 1, wherein said terminal end of said member is planar and is disposed at an angle which is normal to the longitudinal axis of said member.
Claim 5
Dependent Claim
40 words
An applanation tonometer according to claim 2, wherein said terminal end of said member is marked with at least two parallel spaced-apart lines, said lines extending in a direction substantially perpendicular to said circumferential planar wall portion of said member.
Claim 6
Dependent Claim
23 words
An applanation tonometer according to claim 2, wherein the cylindrical surface of said end of said member is coated with a coloring agent.
Claim 7
Dependent Claim
64 words
An applanation tonometer as claimed in claim 1, wherein the weight of the member is determined in accordance with the following formula: F (D/3.06)2 . (P 0.023 (D4 - 3.064)) where, F Force (or weight) exerted by the member measured in tenths of a gram, D Diameter (in millimeters) of a circle applanted by a force F, and P Intra-ocular pressure in mm. Hg.
Claim 8
Dependent Claim
60 words
An applanation tonometer according to claim 1, including: a. a support therefor, said support comprising a sleeve adapted to receive said elongate member in sliding relationship; and b. a holder mounted to one end of said sleeve, said holder incorporating a lamp which is adapted to beam light along the axis of the tonometer member when supported within said sleeve.
Claim 9
Dependent Claim
28 words
An applanation tonometer according to claim 7, wherein said holder also incorporates a removable dry-cell type battery, and a switch in circuit between said battery and said lamp.
Claim 10
Dependent Claim
175 words
An applanation tonometer, comprising, in combination: a. an elongate member of predetermined weight adapted for longitudinal sliding within and from one end of a sliding support therefor; b. at least one end portion of said elongate member being solid and formed from a transparent material having a refractive index approximately equal to that of tear film fluids; c. a terminal end surface of said one end portion of said elongate member being of a prEdetermined cross-sectional area; d. said end portion including a planar wall observation surface which is disposed substantially parallel to the longitudinal axis of said elongate member; e. said terminal end surface being adapted for resting upon the cornea of a subject''s eye; and f. the area of contact between said terminal end of said member and said eye being visible when viewed through said observation surface and at an angle which is obliquely incident to said area of contact by virtue of the end portion of said member having a refractive index approximately equal to that of said tear film fluid.
Claim 11
Dependent Claim
175 words
An applanation tonometer, comprising, in combination: a. an elongate member of predetermined weight adapted for longitudinal sliding within and from one end of a sliding support therefor; b. at least one end portion of said elongate member being solid and formed from a transparent material having a refractive index approximately equal to that of tear film fluids; c. a terminal end surface of said one end portion of said elongate member being of a prEdetermined cross-sectional area; d. said end portion including a planar wall observation surface which is disposed substantially parallel to the longitudinal axis of said elongate member; e. said terminal end surface being adapted for resting upon the cornea of a subject''s eye; and f. the area of contact between said terminal end of said member and said eye being visible when viewed through said observation surface and at an angle which is obliquely incident to said area of contact by virtue of the end portion of said member having a refractive index approximately equal to that of said tear film fluid.
References Cited (Backward Citations)
US3597964A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-02 | 1978-03-04 | 1978-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-02 | 1982-03-04 | 1982-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-02 | 1986-03-04 | 1986-09-03 | $7700.00 | Window Closed / Lapsed |